My 3-year-old son has a habit of holding his two hands tightly closed near his mouth and biting teeth so as to show he's excited. He performs this action only when he plays with toys. It comes naturally from him. Even though I hold his hand, he shows his excitement by biting teeth for one or two seconds.
He is also having delay in speech. OT therapist told me that he is completely normal and just expresses his happiness. He responds to his name and is normal in school and church.
Is there any difference between normal repetitive behaviour and autism? And how to reduce it?